Process for the treatment of cork or a cork-based material particularly with a view towards extracting contaminating organic compounds, in which said cork or said cork-based material is put into contact with a dense fluid under pressure at a temperature of from 10 to 120.degree. C. and at a pressure of from 10 to 600 bars.Manufacturing installation for parts made of cork or a cork-based material, such as bottle corks, comprising an installation for treatment or extraction by putting the said cork or the said material into contact with a dense fluid under pressure.